Using Green Clean to treat Pond Algae

photo credit: bossco
I have a koi pond of approx. 5300 gals. After 1 & 1/2 yrs. of no algae, suddenly after cleaning out bio falls and dead plants I have what appears to be hair &/or string algae growing. Should I use green clean? I think I would need green clean. But I do not know how much it will take to treat my pond for the season.